1. Field of the Invention
The invention in general relates to monitoring of turbine blade vibration, and particularly to the mounting of a narrow beam radar for accomplishing such monitoring.
2. Description of the Prior Art
Various arrangements exist or have been proposed for monitoring rotating turbine blades to determine whether or not they are vibrating. Such vibration can cause fluctuating stresses which can lead to blade as well as turbine damage.
One proposed method for determining turbine blade vibration utilizes a millimeter wave radar system to direct a narrow beam of electromagnetic energy toward the rotating blade row and thereafter analyzing the reflected signal from the blades to detect abnormal vibration. The interior of a turbine represents an extremely hostile environment at a pressure different than that outside the turbine. The use of a millimeter wave radar system as a blade vibration sensor poses a problem in the installation thereof under such adverse conditions. The present invention provides a solution to this problem.